But even before the negotiations start, Britain on Thursday will begin the monumental task of incorporating EU legislation for when the divorce is finalised.

Speaking in parliament on Wednesday, Prime Minister Theresa May said that was important “so that on the day we leave everybody knows those rules still apply and everybody knows where they stand”.

The government will publish a “white paper” policy document on Thursday outlining its plans for the legal overhaul, which for better or worse will give MPs the opportunity to amend the laws as they are brought under the national system.

Britain has until October 2018 at the latest to come up with a draft divorce plan, according to the Commission’s Brexit negotiator Michel Barnier.

While May asserted in January that “no deal is better than a bad deal”, in her Brexit letter she adopted a more conciliatory tone and called for Britain and the EU to “work hard” to avoid failure in the negotiations.

The cliff edge scenario of Britain leaving the European bloc with no deal has alarmed business leaders, who have also emphasised the need for a transitional arrangement to allow for the divorce deal to be gradually implemented.

The European Parliament’s chief Brexit negotiator, Guy Verhofstadt, said such a transition period should be limited to three years.

Tusk is due to issue draft “negotiating guidelines” on Friday and leaders of the 27 remaining EU countries will hold a special summit on April 29 to rubber stamp the plans.

While the bloc has tried to show a united front in the face of Brexit, celebrating the EU’s 60th anniversary earlier this month, in Britain the prime minister is struggling to unite her own country.

Britons last year voted 52 percent to 48 percent in favour of Brexit, leaving the country bitterly divided with tens of thousands of pro-EU protesters marching in London on Saturday.